In the American Heritage Dictionary, third edition, one of the meanings reported for the verb “to jam” is: “to interfere with or prevent the clear reception of . . . signals . . . by electronic means.” In this disclosure, the verb “jam” and its conjugated forms (e.g., “jammed,” “jamming,” “jammer,” etc.) are used, in a somewhat broader sense, to mean: disrupting an unwanted signal of any kind (e.g., radio, optical, acoustic, electrical, etc.) by transmitting an interfering signal of a similar or related kind into the medium (e.g., radio channel or band, optical fiber, waveguide, audio channel or environment, cable or wire or transmission line, etc.) occupied by the unwanted signal, in such a way that the reception of the unwanted signal is disrupted, or prevented or, at least, impaired. Jamming unwanted, unauthorized or threatening communication signals is a technique that is commonly used by military personnel. For example, a jammer that overwhelms a radio channel with interference can be an effective defense against enemy communications in the battlefield. Indeed, disruption of unwanted radio signals is a common application of jamming techniques. Hereinafter this disclosure will use language frequently associated with radio communications and radio signals; however, such language should be understood to have a broader applicability to any kind of signal, as indicated above.
FIG. 1 is a schematic diagram of the salient components of an illustrative signal jammer in the prior art. It is labeled a “basic” signal jammer to highlight the simple architecture of signal jammers that is common in the prior art. Basic signal jammer 100 comprises: receiver 110, transmitter 111-1, transmitter 111-2, and transmitter 111-3, interconnected as shown.
Receiver 110 is a device that receives a description 101 of signals to be transmitted, and converts that description into parameters of jamming signals to be transmitted (hereinafter, “jamming-signal parameters”). Receiver 110 conveys the values of the jamming-signal parameters to transmitters 111-1, 111-2, and 111-3.
Transmitters 111-1, 111-2, and 111-3 transmit jamming signals 102-1, 102-2, and 102-3, respectively. Each signal can be transmitted in a different band, and different signals can be transmitted in different bands at different points in time. In particular, each transmitter can transmit a short burst (hereinafter “pulse”) of interfering signal in one band and, immediately afterwards, transmit another pulse in another band, and so on, in a pattern that is usually repeated periodically in time (hereinafter “temporal transmission pattern”). The specific parameters of the temporal transmission patterns to be transmitted by the three transmitters are provided by description 101 and are incorporated into the jamming-signal parameters by receiver 110.
In typical prior-art jammers, the selection of parameters for the temporal transmission patterns is performed by a human operator of basic signal jammer 100. The human operator usually knows one or more characteristics of the signal, or signals to be jammed, and, based on his or her experience and skill, can generate parameters for the temporal transmission patterns so as to achieve an effective jamming of the unwanted signals.